Summary

• Tests indicate that RISPERDAL oral solution is compatible in the following beverages:  water, coffee, orange juice, and low-fat milk; it is NOT compatible with either cola or tea.¹
• When RISPERDAL oral solution is mixed with either tea or cola, a precipitate forms.^2,3
• It is not known whether the presence of the precipitate affects the efficacy or safety of the solution.  If RISPERDAL oral solution is inadvertently mixed with cola or tea, the dose should not be administered to patients, but should instead be discarded.
• No information is available regarding foods that are compatible with RISPERDAL oral solution.
• The compatibility of RISPERDAL oral solution with bottled water, green tea, black tea, oolong tea, and infusion of parched barley was studied. Insoluble complexes, thought to reduce the available risperidone content, were formed when RISPERDAL oral solution was mixed with tea.²

CLINICAL STUDIES

Compatibility and Stability with Beverages

Aki et al (2006)² investigated The compatibility of risperidone oral solution with select beverages as well as the mechanism for interaction with typical tea tannin. The beverages used to test for compatibility were bottled water, green tea, black tea, oolong tea, and infusion of parched barley. Risperidone oral solution was mixed with each beverage at a volume-to-volume ratio of 3:97. The mixtures were then left to stand at room temperature for 24 hours, over which time the amount of risperidone remaining in the solution was analyzed at intervals by HPLC (high-performance liquid chromatography). The mixed solutions containing tannin and risperidone became cloudy in appearance, and the amount of risperidone remaining in the mixture decreased just after mixing. The ratio of risperidone decrease in the mixture was independent of the amount of tannin contained in the beverage (see Table: Risperidone Oral Solution Stability with Beverages). The investigators did not detect decomposed risperidone in the testing. The water and infusion of parched barley beverages did not contain tannin. When these two beverages were mixed with risperidone oral solution, the risperidone mass/volume remained at or near 100% upon mixing, just after mixing, and 24 hours after mixing.

Risperidone oral solution and a pH 3.0 buffer solution were titrated into each of the test beverages to test compatibility through the measure of heat effect. Unlike the mixtures of risperidone and tea, no significant heat effect was found for risperidone oral solution titrated into bottled water or an infusion of parched barley using ITC (isothermal titration calorimetry). The heat effect was slightly higher for the oolong tea and black tea samples than the green tea samples. The investigators reported that the reaction heat corresponded to the complex formed in solution by risperidone and tannin. The results show risperidone could more easily form a complex with black tea and oolong tea tannin than green tea tannin.

Risperidone oral solution calorimetric titrations with monomeric tea tannin were also examined at pH 3.0 and 25°C. The binding affinity was ten times higher with the tannin TFg (theaflavin 3'-O-gallate), the specific red pigment released from black tea and oolong tea, than other tea tannins studied. The risperidone and tea tannin solutions became cloudy and produced white precipitates when left to stand overnight.

The authors concluded that the insoluble complexes formed when risperidone oral solution was mixed with tea reduced the available risperidone content.

LITERATURE SEARCH

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, and DERWENT Drug File (and/or other resources, including internal/external databases) pertaining to this topic was conducted on 04 April 2024.